Modifying stacked bathroom plumbing

I'm in the process of putting new vanities in my 2 bathrooms which are stacked on top of each other. The water plumbing for the bottom bath comes through the floor where I would prefer it coming through the wall. The upstairs bath comes through the wall already. The runs to each are 1/2 copper tapped from a 3/4 copper main in the basement. Would there be anything wrong with opening up the wall in the bottom bathroom and installing T's into the line going to the upper bathroom? I wasn't sure if that would cause pressure issues. The showers have their own lines. These are just for single sinks in each bathroom.

I'd appreciate any input ya'll have. If I just need to leave them through the floor, I think I can manage it. The vanity isn't here yet but I'm fairly certain I can drill through the bottom to get the lines up to the new sink.